Programmed venous assist pump

ABSTRACT

An apparatus for providing circulatory assistance to a bed patient to preclude the pooling or clotting of venous blood in the legs or other extremities. A plurality of pairs of pressure cuffs are disposed along the legs of a patient needing circulatory assistance. Programming means are provided to facilitate the sequential inflation of said pressure cuffs, in such a manner that a progressive pressure wave travels up the patient&#39;&#39;s legs pushing the venous blood ahead of it.

United States Patent .1 Apstein PROGRAMMED VENOUS ASSIST PUMP [76] Inventor: Maurice Apstein, 4611 Maple Ave.,

Bethesda, Md. 20014 [22 Filed: Jan. 17,1973

21 Appl. No.2 324,266

[52] US. Cl. 128/64, l28/DIG. IO [51] Int. Cl A6lh 7/00 [58] Field of Search 128/24 R, 64, 60, DIG. 10

' [56] References Cited UNITED STATES PATENTS in] 3,811,431 5] May 21, 1974 Primary Examiner-Lawrence W. Trapp Attorney, Agent, or Firm-Edward J. Kelly; Herbert Berl; Saul Elbaum [57] ABSTRACT An apparatus for providing circulatory'assistance to a bed patient to preclude the pooling or clotting of venous blood in the legs or other extremities. A plurality of pairs of pressure cuffs are disposed along the legs of a patient needing circulatory assistance. Programming means are provided to facilitate the sequential inflation of said pressure cuffs, in such a manner that a progressive pressure wave travels up the patients legs 2,781,041 2/1957 Weinberg 128/24 R pushing the venous blood ahead of it. 3,390,674 7/1968 Jones 1281DlG. 10

5 Claims, 9 Drawing Figures E 24 16 1e I P W COMPRESSED REGULATOR p PRESSURE I AIR VALVE P GAUGE I 1 J T I I2 9 l l l I ACCUMULATOR I l J 14 i i jATENTEDHAYZl L9H.

SHEET 2 0f 2 CUFFS 0 60 60|20 |20l80 |80 360 A-A INFLATE CLOSE CLOSE EXHAUST B B CLOSE INFLATE CLOSE EXHAUST c-c CLOSE CLOSE INFLATE EXHAUST CUFF CUFF CUFF TANK TANK TANK A B c 0 O5 A c FLIP FLIP FLIP RA FLOP SA RB FLOP 38 RC FLOP 50 A B c L 40 L L LL LL A AIR SUPPLY F/6 6 l PROGRAMMED VENOUS ASSIST PUMP ORIGIN OF INVENTION The invention used herein may be manufactured, used and licensed by or for the U.S. Government for Governmental purposes without the payment to us of any royalty thereon.

BACKGROUND OF INVENTION 1. Statement of Invention The present invention relates to a system and apparatus for preventing the pooling of venous blood in the extremities of patients. More specifically, the present invention relates to a programmed venous assist pumping means is safe to use in the explosive environment of operating rooms.

2. Description of Prior Art The pooling of blood in the extremities of bedpatients is quite common due to the inactivity of the patients. This is particularly true of post-coronary patients. since the impaired heart does not have the capacity to return the blood through the venous system to the heart. It is known that the pooling of blood can be kept to a minimum by massaging the extremities of the patient either by hand or with the aid of a plurality of sequentially inflatable pressure devices wrapped around the extremities ofa patient. Devices of this type are generally known in the art.

It was recently discovered that similar devices would be useful for preventing clot formation during surgery by intermittently compressing the extremities of a patient while on the operating table. However, the potentially explosive environment of operating rooms limits the design possibilities of the apparatus which can be used therein. For example, the use ofelectrical components should be avoided, since sparking or arcing could lead to a severe explosion. Also the devices employed should be compact and portable. Known prior art devices do not meet these requirements and are, therefore. not suitable for use in preventing blood clots or venuous pooling during surgery.

SUMMARY OF INVENTION Accordingly, itis an object of the present invention to provide a venous assist pump suitable for use in operating rooms.

It is another object of the present invention to provide a venous assist pump which is compact and quiet in operation.

It is still another object of the present invention to provide a venous assist pump which does not require the use of electrical components in the explosive environments of operating rooms.

It is a further object of the present invention to provide a programming means for the venous assist pump comprised of purely fluidic or flueric components.

It is a still further object of the present invention to provide a novel mechanical programming means including a valve means driven by an adjustable timing means.

These and other objects of the present invention are accomplished by securing a plurality. of pairs of pressure cuffs. similar to those used in blood pressure measuring devices, around the extremities of a patient. For example, in a preferred embodiment a first pair of pressure cuffs is wrapped around the patient's ankles a second pair around the mid calves and a third pair pair around the upper calves or lower thighs. These pressure cuffs are sequentially inflated beginning with said first pair at the ankle until all three pairs of cuffs become inflated. All of the cuffs are then simultaneously deflated. The cycle is then repeated to create a progressive compressional wave which travels up the patients leg pushing the venous blood ahead of it. The timing cycle of inflation may be varied depending on the needs or comfort of the particular patient being treated.

The sequential inflation of the pressure cuffs is controlled by a programming means which regulates the supply of compressed air to the respective pairs of pressure cuffs. In one embodiment of the present invention the programming means consists of the combination of a rotating valve driven by a timing motor. For example, the timing mechanism of a wind-up-clock may be employed to rotate the programming valve means. In a second embodiment of the present invention a purely flueric. or fluidic programming means may be used including a plurality of flueric or fluidic bistable flip-flops. Both embodiments or programming means of the present invention are devoid of any electrical components and, therefore, may be safely used in the explo-' sive environment of an operating room. In a third em- The objects of the present invention and the atten-' dant advantages thereof will become more fully apparent with reference to the drawings and the following description thereof, wherein:

FIG. 1 is a schematic diagram illustrating a first embodiment of the programmed venous assist pump of the present invention;

FIG. 2 is an end view in section of a programming valve means of the present invention;

FIG. 3 is a side view of the'programming valve means illustrated in FIG. 2;

FIGS. 4A to 4D are bottom plan views illustrating the operation of the programming valve means of FIGS. 2 and 3;

FIG. 5 is a chart illustrating a preferred program for inflating the pressure cuffs of the present invention; and

FIG. 6 is a schematic diagram of a second embodiment of the venous assist pump of the present invention having a flueric or fluidic programming means.

Referring to FIG. 1 in more detail, there is generally shown an air supply means 10 including a source of compressed air 12 including a pump for pumping compressed air into an accumulator tank 14. In the alternative a tank of compressed air may be used in place of the pump. Accumulator tank 14 is connected to a regulator valve 16. A pressure gauge 18 is in turn connected to regulator valve 16 to control the pressure of compressed air passing through regulator valve 16. In addition accumulator 14 may have a pressure regulator therein to keep the internal pressure at a desired level. Pressure gauge 18 may be an automatic device with a feed back path 19 to regulator valve 16 or in the alternative pressure gauge 18 may be a meterwhich an operator observes and manually adjusts regulator valve 16 in accordance with the meter reading. Pressure gauge 18 is disposed in any or all of lines P P and Pg connected to a valve means 24 which is driven by suitable timing means 22. Valve means 24 and timing means 22 constitute a programming means 21 which may either be a mechanical means as illustrated in FIGS. 2 and 3, or a purely flueric or'fluidic programming means as illustrated in FIG. 6 to be described more fully hereinafter. Programming means 21 has outputs connected to a plurality of pairs of pressure cuffs AA, 8-H and CC respectively. In a preferred embodiment the cuffs of pair AA are disposed around the ankle of the patient to be treated; the cuff pair BB is placed around the mid-calf of the patient to be treated; and the cuff pair C-C may be placed either around the upper calf of the patient to be treated or the lower thigh as desired.

Referring to the operation of thesystem of FIG. I, the cuffs are wrapped around the legs of the patient in pairs in the manner indicated above. When pump 12 is energized it fills accumulator 14 to some convenient pressure for example lOto PSI. This air bleeds through regulator valve 16 at a lower pressure determined by its setting and the indication or monitoring function of pressure gauge 18. From there the air begins to inflate the various pairs of cuffs in a sequence determined by programming means 21.

As the air passes to the respective pairs of cuffs in accordance with the control by programming means 21, the respective cuffs begin to inflate starting with cuff pair AA around the ankles. After cuffs A-A are inflated the intake valve for that pair closes and the pressure is maintained in the cuffs. Next the programmer opens the intake valve of cuff pair B-B and inflates them. Then this valve closes and the pressure in cuff pair BB is maintained. Next the programmer inflates cuff pair CC and holds it inflated for a specified period oftime. Finally the programmer opens all three exhaust valves and the pressure in all cuffs is released and all cuffs deflate-The net result of the above program is that a pressure valve travels upwards toward the knees in a slow progression gently forcing venous blood to return to the heart.

In a preferred embodiment of the present invention cuff pairs AA, BB and C-C are rubber bags similar to the pressure cuffs used in measuring blood pressure. However, any other-form of pressure cuff means may be employed without departing from the spirit and scope of this invention.

Referring to FIGS. 2 to 4, there is shown a rotary valve means generally'designated 24. Rotary valve 24 includes a housing 26 formed of a hexagonal plastic or square rod having a central substantially cylindrical longitudinal .bore therein. A plurality of holes 30 are provided in the surface of housing 24 in communication with the longitudinal bore therein. Holes 30.are provided at substantially right angles to the direction of said longitudinal bore and consistof three-sets of three holes. These nine holes act as input and exhaust ports. A cylindrical rotor 28 is disposed for rotation in the longitudinal bore of valve housing 25. In a preferred embodiment rotor 28 is simply a plastic rod with flats in FIGS. 4 and 5 is merely a preferred embodiment of or channels 28A milled into its surface, so that as it roeach other. Theletter P designates-the source of pressure for cuff pair A-A which is supplied through pressure gauge 18, as shown in FIG. 1. The letter C represents the connection between programming means 21 and pressure cuff pair A-A. The letter E designates the exhaust port for cuff pair A-A. In a like manner the letters P C and E refer to the respective pressure sources, inlet means, and exhaust means of cuff pair B-B. in the same manner the letters P ,-C and E represent the pressure source, inlet means, and exhaust means for cuff pair C-C. The flats or channels 28A in rotor 28 of valve means 24 may be milled in any desired way to provide any desired sequence of energization of the respective cuff pairs A-A, B -B and C--C respectively. In a preferred embodiment rotor 28 is divided into three 60 sectors and one 180 which are sequentially rotated past holes 30. For example, the first 60 sector is provided with a flat or channel 28A as shown in FIG. 4A which connects hole P to hole (3; as it is rotated 'into alignment therewith. This causescompressed air to be supplied to cuff pair A- A which is thereby inflated. As the next'60 sector of rotor 28, as shown in FIG. 4B, is rotated into alignment with holes 30, holes P C and E and P C and E are all closed while a flat or channel'portion 28A- is moved into alignment with hole P land C -to provide'communication therebetween. This, of course, facilitates the inflation of cuff pair 8-8. As the next 60"sector of rotor 28 is rotatedinto alignment with 'hole 30, as shown in FIG. 4C, holes P C 5,, P C and E}, are

closed and a flat or channel 28A'move's into alignment with holes P and C This causes cufl pair C-C to be inflated. Rotor 28 continues to rotate until the l holes C E and C E respectively are connected together by flats or channels 28A. This facilitates the deflation of all cuff pairs simultaneously in preparation for the next successive cycle of operation.

Referring to FIG; 5 there isshown achart which fur- 1 ther explains the operation of the valve means 24 of FIGS. 2 to 4. The left hand coluinndesignates the cuff pairs and the corresponding rows in thesuccessive col umns to the right illustrate the condition of said cuff pairs as rotor 28 makes one complete'revolution.'

It should be understood that the program illustrated no electrical components therein. Forexarnple, motor 22 may be similar to a wind-up clock mechanism. In other words it may be a wind-up spring type motor. It may be provided with means for adjusting the speed of rotation to thereby facilitate the control of the rate at which the compressional wave is directed up the extremity of a patient. This is very important because different rates may be desirable for different patients and different conditions for which they are being treated. The use of purely mechanical components in motor 22 facilitates the safe use thereof in the explosive environments of operating rooms.

The entire valve means 24 may be fabricated of light weight plastic or other synthetic materials which decreases the costs of manufacture and enhances the portability of the device.

Timing means 22 may, alternatively, consist of an electrically driven motor in which case the programming means 21 would be located outside the operating room and only a triple air hose would lead into the operating room.

Referring to FIG. 6 there is shown a purely fluidic or flueric programmer comprising aplurality of fluidic or flueric bistable flip-flops A, B, and C, respectively. Any suitable type of flueric or fluidic flop-flop may be used as would occur to one of ordinary skill in the art. Flipflops A, B and C are connected to pressure input lines P P and P which are in communication with air supply 10. Air supply 10 maybe of the same type described in the embodiment of the present invention il-.

lustrated in FIG. 1. Each flip-flop. A, B, and C has a set terminal S, and a reset terminal, R, designated S R S,,, R,,; and S R respectively. Each flip-flop A, B and C is connected to a set of pressure cuffs and an associated accumulator tank. As illustrated in FIG. 6 flipflop A is connected to pressure cuffs AA through line C, and to tank A through line T flip-flop B is connected to pressure cuffs BB through line C and to tank B through line T and flip-flop C is connected to cuffs C-C through line C and to tank C through line T,-. There are no pressure switches." The switching pressure is determined by the flip-flop design and the size of the tank determines the delay. As will become more fully apparent hereinafter the tanks A, B, C comprise a timing means which controls the switching pres-- sure and the sequence of the flip-flops A, B, C and hence the sequential rate of inflation of cuffs AA, BB and CC.

In operation flip-flops A and C are biased so that at the beginning ofa cycle they are in the set position and flip-flop B is in the reset position. In the set position each respective flip-flop connects its pressure input line to the respective output line leading to the associated cuffs. In the reset position each flip-flop connects its associated input line to its associated tank.

Thus, when air is supplied through lines P P and P with flip-flops A and C in the set position and flipflop B in the reset position. line P is connected to line C, which inflates cuffs A--A; line P is connected to line C which inflates cuffs CC; and line P is connected to line T which fills tank B. When the pressure in tank B reaches some predetermined level, determined by the switching threshold of the flip-flop, a pressure signal is generated through line 0 which switches flip-flop B to the set position and flip-flop C to the reset position. This relieves the pressure in cuffs C--C and allows compressed air to be supplied to tank C through lines P,- and T When the pressure in tank C reaches a predetermined level, a signal is transmitted through lines 0 and 40 to reset flip-flop A. This permits cuffs AA to drain and tank A to fill up to some predetermined level of pressure. Thus the process continues so that a pressure wave progresses from cuffs AA to BB to CC. Of course other programs may be used without departing from the spirit and scope of this invention.

It should be understood that the present invention is not limited to the exact details of construction shown and described, for obvious modifications can be made by a person skilled in the art.

l claim:

1. In a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, aplurality of pressure cuff means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressed fluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the'selected portion of said patient which pushes the venous blood ahead of it toward the patients heart, said programming means inface of said housing communicating with said longitudinal bore, each of said sets ofholes including a fluid inlet hole, a fluid outlet hole, and an exhaust hole;

b. means for connecting the fluid inlet hole of each set to said source ofcompressed fluid; c. means for connecting said fluid outlet hole of each set to a selected pressure cuff means;

d. means for connecting said exhaust hole of each set to the atmosphere; and

e. a substantially cylindrical rotor means, journaled in said longitudinal bore, the cylindrical periphery of said'rotorbeing in sealing engagement with said sets of holes, said rotor means being divided into a plurality sectors, each of said sectors having depressions milled therein at selected locations for alignment with selected combinations of said fluid inlet holes, said fluid outlet holes, and said exhaust holes in each respective set of holes as said sectors of said rotor means are rotated past said face of said housing means in response to the operation of said timing motor, whereby said milled depressions permit the flow of fluid between the selected combinations of holes with which said'milled depressions are aligned in each respective set.

2. The invention of claim I wherein there is provided three of said sets of holes, each of said sets being associated with a selected pressure cuff means.

3. The invention of claim 1 wherein said timing motor may be adjusted to vary the speed of rotation of said motor.

4. In a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, a plurality 'of pressure cuff means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressed fluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the selected portion of said patient which pushes the venous blood ahead of it toward the patients heart, the improvement comprising a fluidic programming means including:

a. a plurality of bistable fluidic switching means connected between said source of compressed fluid and a corresponding number of said pressure cuff means; and

b. tank means association with each of said pressure cuff means having input means connected to each of said bistable fluidic switching means, means for generating an output signal in response to the pressure built up in each of said tank means, said output signals being applied to selectedswitching terminals of said bistable fluidic switching means to thereby control the timing cycle of said bistable switching means and the supply of fluid to said pressure cuff means. 5. in a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, a plurality of pressure cult means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressedfluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the selected portion of said i put signals being applied to selected switching terminals of said bistable flueric, switching means to thereby control the timing cycle of said bistable switching means and the supply of. fluid to said pressure culT means. 

1. In a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, a plurality of pressure cuff means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressed fluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the selected portion of said patient which pushes the venous blood ahead of it toward the patient''s heart, said programming means including a valve means, and a timing motor for operating said valve means, the improvement comprising a valve means including: a. a housing having a substantially cylindrical longitudinal bore therein, a plurality of sets of holes in a face of said housing communicating with said longitudinal bore, each of said sets of holes including a fluid inlet hole, a fluid outlet hole, and an exhaust hole; b. means for connecting the fluid inlet hole of each set to said source of compressed fluid; c. means for connecting said fluid outlet hole of each set to a selected pressure cuff means; d. means for connecting said exhaust hole of each set to the atmosphere; and e. a substantially cylindrical rotor means, journaled in said longitudinal bore, the cylindrical periphery of said rotor being in sealing engagement with said sets of holes, said rotor means being divided into a plurality sectors, each of said sectors having depressions milled therein at selected locations for alignment with selected combinations of said fluid inlet holes, said fluid outlet holes, and said exhaust holes in each respective set of holes as said sectors of said rotor means are rotated past said face of said housing means in response to the operation of said timing motor, whereby said milled depressions permit the flow of fluid between the selected combinations of holes with which said milled depressions are aligned in each respective set.
 2. The invention of claim 1 wherein there is provided three of said sets of holes, each of said sets being associated with a selected pressure cuff means.
 3. The invention of claim 1 wherein said timing motor may be adjusted to vary the speed of rotation of said motor.
 4. In a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, a plurality of pressure cuff means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressed fluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the selected portion of said patient which pushes the venous blood ahead of it toward the patient''s heart, the improvement comprising a fluidic programming means including: a. a plurality of bistable fluidic switching means connected between said source of compressed fluid and a corresponding number of said pressure cuff means; and b. tank means association with each of said pressure cuff means having input means connected to each of said bistable fluidic switching means, means for generating an output signal in response to the pressure built up in each of said tank means, said output signals being applied to selected switching terminals of said bistable fluidic switching means to thereby control the timing cycle of said bistable switching means and the supply of fluid to said pressure cuff means.
 5. In a programmed venous assist pump for providing circulatory assistance to a patient including a source of compressed fluid, a plurality of pressure cuff means adapted to be disposed around selected portions of said patient, programming means for selectively connecting said source of compressed fluid to selected pressure cuff means in a predetermined sequence to generate a compressional wave along the selected portion of said patient which pushes the venous blood ahead of it toward the patient''s heart, the improvement comprising a flueric programming means including: a. a plurality of bistable flueric switching means connected between said source of compressed fluid and a corresponding number of said pressure cuff means; and b. tank means associated with each of said pressure cuff means having input means connected to each of said bistable flueric switching means, means for generating an output signal in response to the pressure built up in each of said tank means, said output signals being applied to selected switching terminals of said bistable flueric switching means to thereby control the timing cycle of said bistable switching means and the supply of fluid to said pressure cuff means. 